The effect of growth-dependent mortality, external environment and internal dynamics on larval fish otolith growth: an individual-based modelling approach
Authored by A Gallego, M Heath
Date Published: 1997
DOI: 10.1111/j.1095-8649.1997.tb06096.x
Sponsors:
European Union
Platforms:
No platforms listed
Model Documentation:
Other Narrative
Model Code URLs:
Model code not found
Abstract
The daily otolith increment growth of individuals in a cohort of fish
larvae was simulated by a simple individual-based model over 30 days.
The daily otolith growth of an individual larva was dependent on past
growth, within fixed limits common to all larvae. The survival of a
larva at the end of each day was either a linear function of larval
growth or a random outcome, simulating growth-dependent and
growth-independent mortality, respectively. The combined effect of the
external environment on growth was also studied. Eleven environmental
scenarios, favouring or hindering growth at different stages, were
tested and compared to runs with no environmental effect on growth.
Growth-dependent mortality induced an increase in the average otolith
daily increment width amongst surviving larvae. Such an outcome, however, could be negated by an unfavourable environment. The increase
in mean growth rate of the population generated by growth-dependent
mortality was directly related to the inherent variability in daily
otolith growth. With increased variability, the influence of the
environment became relatively less important. The effect of the
environment on growth was more critical during the early stages of
development. A comparison of results generated by the model with
patterns observed in data from a field survey of larval herring was
consistent with the occurrence of growth-dependent mortality in the sea.
The simulation model provided a useful insight into the way in which
various processes controlling larval growth interact.
Tags
Predation
microstructure
Recruitment
Inferences
Variability
Life
Survival
Cod gadus-morhua
Marine fishes
Clupea-harengus l